Osteoporotic fractures and vitamin D deficiency

A caucasian woman aged 79 years, with a history of hypertension, hyperlipidaemia, and osteoarthritis, was referred for assessment of osteoporosis and generalised musculoskeletal pain after surgery for a right midshaft femoral fracture. Further history revealed she had suffered nonspecific musculoskeletal pain, particularly of the pelvic girdle, and unsteady gait for many weeks, but denied suffering any falls. She had limited mobility due to osteoarthritis of both knees. She had been mostly housebound and was on an animal product restricted diet in view of her history of hypercholesterolaemia. Initial X-rays confirmed an incomplete fracture of the midshaft of the right femur. She had an orthopaedic review, and subsequent bone scan and X-rays (Figure 1) revealed incomplete fractures of the midshaft of both femurs and the seventh rib. She was managed conservatively (alendronate 70 mg per week) and progress was closely monitored. Three weeks later, she presented to the emergency department with worsening right thigh pain and difficulty in weightbearing. X-rays revealed an extension of the right femoral fracture traversing the entire cortex that required surgery. Physical examination revealed a mild thoracic kyphosis. There was no muscle or bone tenderness, proximal muscle weakness, or other significant abnormality. The plasma biochemistry revealed: mild hypocalcaemia (1.98 mmol/L), hypophoshataemia (0.7 mmol/L), raised alkaline phosphatase (ALP) (216 iu/L), low 25-hydroxyvitamin D (250HD) (22 nmol/L), and a mildly raised parathyroid hormone (PTH) level (8 pmol/L). Thyroid, renal, and liver functions were normal. The patient was treated with nine capsules of Ostelin 1000 per day, which was tapered over 8 weeks to one capsule. The repeat plasma 25OHD after 6 weeks was 56 nmol/L, and her musculoskeletal symptoms were completely resolved. There was normalisation of biochemical abnormalities and X-rays demonstrated healing of both femoral fractures. A bone biopsy taken at the time of surgery revealed an increased amount of osteoid. However, undecalcified bone sections were not examined, nor was quantitative histomorphometry performed. Dual energy X-ray absortiometry (DEXA) scan revealed a T-score of -3.32 at the hip and -1.38 at the lumbar spine. Corresponding Z-scores were -1.05 and -0.7.